Thermocouple return bend and well



uly 10, 1951 -rr 2,560,455

THERMOCOUPLE RETURN BEND AND WELL Filed May 26, 1949 FIG. 2

H W ////////IIIIIII/I///IIII/IIIII(// IN V EN TOR.

T.H. NIGHT BY); t f

A TTORNEVS Patented July 10, 1951 2,560,455 THERMOCOUPLE RETURN BEND AND WELL Thomas H. Knight, Phillips, Tex., assignor to Phillips Petroleum Company, a corporation of Delaware Application May 26, 1949, Serial No. 95,458

Claims.

This invention relates to a return bend containing a well for a thermo-sensitive instrument. In one specific aspect it relates to a return bend containing a well which is disposed out of the path of abrasive particles. Other specific aspects relate to wells for thermo-sensitive instruments.

In the art of cooling and more especially of heating fluids it is customary to carry out the .heat exchange in a number of straight lengths of pipe each pipe connectedto an adjacent pipe by a U-shaped pipe known as'a return bend. The return bends often project from the end of the heat exchanger, or furnace, and therefore I locate my well for a thermo-sensitive instrument in the return bend.

One object of the present invention is to provide an improved return bend and well.

Another object is to locate a well for a thermosensitive instrument in a return bend in such a manner that abrasion is reduced.

Another object is to provide an improved well for a thermo-sensitive instrument.

Numerous other objects and advantages will be apparent to those skilled in the art upon reading the accompanying specification, claims and drawings.

In the drawings:

Figure 1 is an elevational view of a return bend embodying the present invention.

Figure 2 is a cross sectional view taken along the line 2-2 of Figure 1 looking in the direction indicated, but with a thermo-sensitive instrument not shown in Figure 1 installed in the well.

Figure 3 is a cross-sectional view of the well shown in Figures 1 and 2, the cross section being taken through the longitudinal axis of said well.

In Figure 1 a return bend generally designated as 4 comprises a u-shaped piece of pipe 6 con taining a U-shaped passage 1 disposed to direct a fluid 8 (which may be a liquid or a gas, but which is shown; as a liquid in Figure 2) through a 180 turn. l i'pe 6 has suitable connection means 9 and on its ends for forming a seal with the straight pipes of the heat exchanger (not shown). While a heat exchanger is referred to, and generally the heat exchanger is for heating the fluid 8 rather than cooling the same, other non-thermochanges may take place in these straight pipes and return bends. For example, some sort of contacting of fluids may occur, or mixtures of fluids and solids, all without changing the present invention which relates to a return bend 4 which may be used for any purpose to which return bends are put in the prior art.

Connection surfaces 9 and II may be any type known to the prior art, and may be intemal'or external, screw threaded or smooth, the type shown being adapted to be forced against a soft seat to forma seal or else welded to the adjacent straight section of pipe. The manner ofconnection of the return bend does not change the invention.

When return bend 4 is to be held in place by some clamping means, this clamping means may include screws engaging lugs I2 and I3. When return bend 4 is to be welded to the straight pipes -(not shown) then lugs l2 and I3 are unnecessary and may be omitted.

Similarly a handle I4 is supplied on most'return bends which is useful in assembling and disassembling the heat exchanger, but which is not essential. Handle l4 may be omitted.

Pipe 6 has a bore "5 connecting passage 1 with the exterior at a point in the center portion of pipe 6, said bore |6 having an outer screw thread portion I1 and an inner conical seat portion I8. Portions l1 and 3 may be formed in the wall of 6 as boss l9 can be formed integral with pipe 6. However, boss I9 is shown as a separable element because these devices are being made this way at persent, boss I9 being built up by welding with a 25 to 20 stainless steel welding rod. In large scale manufacturing, it is preferred to make boss l9 integral with pipe 6 rather than as shown.

The axis of bore I6 is normal to the plane of the U-shaped passage 1 as shown in Figure 2 so that the well, generally designated as 2| will extend out into the central portion of fluid 8 without passing through the portion of the U-shaped passage where centrifugal force tends to throw solid particles such as 22.

Well 2| comprises a pipe 23 having central passage 24 open at its outer end 26 but closed at its inner end 21. Well 2| is secured in bore IS with its closed end 21 extending into the passage, screw threads 28 on the exterior of the well engaging screw threads l1 and conical surface 29 on the well engaging conical seat l8. To aid assembly and disassembly of the well a non-circular tool engaging portion 3| is provided.

Obviously other means of securing well 2| in bore I6 ma be employed with valuable results but screw threads 28 and conical seat 29 are preferred.

While the position of well 2| in the center of passage 1 is out of the path of the heavier particles 22, which are thrown to the outside by centrifugal force as they travel around the U-shaped passage, nevertheless, well 2| is subjected to wear and therefore it is preferred to cover at least that portion of pipe 23 which extends into the passage 1 with a welded on layer of hard metal 32. It is preferable in fact to have conical seat 29'covered with this same layer of hard metal 32 and surface 29 is made smooth by grinding the same in order to flt seat l8. While not essential it is preferable to also grind the outside of surface 33 and round the nose 34 by grinding the same.

Layer 32 may be any one of a number of hard metal o metal alloys which may be applied by any process known to the prior art, but it is preferred to deposit layer 32 on the well 2| by welding and building it up from a melted welding rod (not shown) such a method being old for making hard surfaces on objects such as drill bits and the like.

However, as the metal to be used for layer 32, I prefer to use Stellite, a trade-marked product which has the following composition:

Per cent Cobalt -80 Tungsten 0-25 Chromium (preferably 20-35% chro- 25 mium) 10-40 Carbon (preferably 0.752.5% carbon) 0- 2.5 Silica 3 Operation As shown in Figure 2 in operation the fluid passing through return bend 4 has its direction of motion changed by 180. This change in the direction of motion results in annular accelerations so that heavier solid particles 22, which may be present in fluid 8, are carried by centrifugal force to the outside of the U-shaped bend 6 so that well 2| is not in their path, thus reducing the amount of wear on well 2|. As well 2| is more likely to wear out before the pipe 6 does, the result is to lengthen the life of the return bend 4.

The embodiment shown in the drawings and described in the specification was chosen for illustrative purposes as a preferred form of the invention, the scope of which is defined in the following claims.

Having described my invention, I claim:

1. A return bend and well for a thermo-sensitive instrument comprising in combination a piece of pipe having a U-shaped passage therein disposed to direct a fluid through a turn, said pipehaving a bore connecting said passage to the exterior at a point in the central portion of said pipe, said bore having an outer screw threaded portion and an inner conical seat portion, the axis of said borebeing normal to the plane containing th axis of the U-shaped passage, and a Well comprising a pipe having a central passage open at its'outer end but closed at its inner end secured in said bore with the closed end extending into the passage along the axis of said bore and spaced from theinner wall along the outside radius of said U-shaped passage whereby solid particles in the fluid flowing through said U-shaped passage tend to be carried by centrifugal force in a path out of contact with said well, screw threads on the exterior of said well engaging said screw threaded portion, and a conical surface on the exterior of said well sealing against, said conical seat portion, at least that portion of said well extending into said passage being coated with a. welded on layer of hard metal Stellite.

2. A return bend and well comprising in combination a piece of pipe having a U-shaped passage therein disposed to direct a fluid through a turn, said pipe having a bore connecting said passage to the exterior at a point in the central portion of said pipe, said bore having an outer screw threaded portion and an inner conical seat portion, the axis of said bore being normal to the plane containing the axis of the U-shaped passage, and a well comprising a pipe having a central passage open at its outer end but closed at its inner end secured in said bore with the closed end extending into the passage along the axis of said'bore "and spaced from the inner wall along the outside radius of said U-shaped passage whereby solid particles in the fluid flowing through said U-shaped passage tend to be carried by centrifugal force in a path out of contact with said well, at least'that portion of said well extending into said passage being coated with a weldedon layer of hard metal.

3. A return bend and well for a thermo-sensitive instrument comprising in combination a piece of pipe having a U-shaped passage therein disposed to'direct a fluid through a turn, said pipe having a bore connecting said passage to the exterior at a point in the central portion of said pipe, said bore having an outer screw threaded portion and an inner conical seat portion, the axis of said bore being normal to the plane containing the axis of the U-shaped passage, and a well comprising a pipe having a central passage open at its outer end but closed at its inner end secured in said-bore with the closed end extending into the passage along the axis of said bore and spaced from the inner wall along the outside radius of said U-shaped passage whereby solid particles in the fluid flowing through said U- shaped passage tend to be carried by centrifugal force in a path out of contact with said well, screw threads on the exterior of said well engaging said screw threaded portion, and a conical surface on the exterior of said well sealing against said conical seat portion.

4. A return bend and well comprising in combination a piece of pipe having a U-shaped passage therein disposed to direct a fluid through a turn, said pipe having a bore connecting said passage to the exterior at a point in the central portion of said pipe, the axis of said bore being normal to the plane containing the axis of the U-shaped passage, and a well comprising a pipe having a central passage open at its outer end but closed at its inner endsecured in said bore with the closed end extending into the passage along the axis of said bore and spaced from the inner wall along the outside radius of said U- shaped passage whereby solid particles in the fluid flowing through said -shaped passage tend to be carried by centrifugal force in a path out of contact with said well, at least that portion of said well extending into said passage being coated with a welded on layer of hard metal.

5. A return bend and well comprising in combination a piece of pipe having a U-shaped pas- 5 sage therein disposed to direct a fluid through a turn, said pipe having a bore connecting said passage to the exterior at a point in the central portion of said pipe, the axis of said bore being normal to the plane containing the axis of the U-shaped passage, and a well comprising a pipe having a central passage open at its outer end but closed at its inner end secured in said bore with the closed end extending into the passage along the axis of said bore and spaced from the inner wall along the outside radius of said U- shaped passage whereby solid particles in the fluid flowing through said U-shaped passage tend to be carried by centrifugal force in a path out of contact with said well.

THOMAS H. KNIGHT.

REFERENCES CITED The following references are of record in the file of this patent? UNITED STATES PATENTS Number Name Date 1,233,385 Mauer July 17, 1917 2,159,705 McCoy May 23, 1939 OTHER REFERENCES Catalog 1402, page 48, 1926, published by the Bristol 00., Waterbury, Connecticut.

Welding Journal, pages 744 and 745, 1946. 

